Modern communication and data networks comprise network nodes, such as routers, switches, bridges, and other devices that transport data through the network. Over the years, the telecommunication industry has made significant improvements to the network nodes to support an increasing number of protocols and specifications standardized by the Internet Engineering Task Force (IETF). Creating and coupling the complex network nodes to form networks that support and implement the various IETF standards (e.g. virtual private networks requirements) has inadvertently cause modern networks to become labyrinth-like and difficult to manage. As a result, vendors and third-party operators continually struggle to customize, optimize, and improve the performance of the interwoven web of network nodes.
For example, MPLS networks have evolved over the last 10-15 years to become critically important for ISPs. They provide two key services: traffic engineering in IP networks and L2 or L3 enterprise VPNs. However as carriers deploy MPLS networks, they find that (a) even though the MPLS data plane was meant to be simple, vendors end up supporting MPLS as an additional feature on complex, energy hogging, expensive core routers; and (b) the IP/MPLS control plane has become exceedingly complex with a wide variety of protocols tightly intertwined with the associated data-plane mechanisms.
In recent years, Software defined networking (SDN) is an emerging network technology that addresses customization and optimization concerns within convoluted networks. SDN simplifies modern networks by decoupling the data-forwarding capability (e.g. a data plane) from routing, resource, and other management functionality (e.g. a control plane) previously performed in the network nodes. Network nodes that support SDN (e.g., that are SDN compliant) may be configured to implement the data plane functions, while the control plane functions may be provided by a SDN controller. Open application programming interface (API) services, such as the OpenFlow protocol, may manage the interactions between the data plane and control plane and allow for the implementation of non-vendor specific combinations of networking nodes and SDN controllers within a network. As a result, SDN in conjunction with an Open API (e.g., OpenFlow) service may provide numerous benefits to modern networks that include increased network virtualization, flexible control and utilization of the network, and customization of networks for scenarios with specific requirements.
A new approach to MPLS that uses the standard MPLS data-plane with a simpler and extensible control-plane based on SDN principles and OpenFlow API for signaling the control plane decisions to the data plane. There are significant advantages in using this approach. The control-plane is greatly simplified and is de-coupled from a simple data-plane. And we can still provide all the services that MPLS networks provide today. More importantly we can do much more: we can globally optimize the services; make them more dynamic; or create new services by simply programming networking applications on top of the SDN Controller. However, problems still exist when using SDN with a MPLS core.
Namely, before each host communicates with another host in the Layer 2 domain, it uses Address Resolution Protocol (ARP) to resolve the MAC address of target host by broadcasting ARP request datagrams. Once ARP reply is received with the target MAC address, this resolved MAC address is kept in a local cache. This cached value is expired on a periodic basis to allow the target host to move or for the network to dynamically change the IP address allocation using DHCP. This makes it essential to frequently broadcast ARP requests at the L2. When there are 100s of 1000s of hosts, this amounts to large amounts of overhead traffic in the network and increased setup time for communication between hosts. In addition, the ARP resolution could also span over the high-latency MPLS core which exacerbates the issue. Thus, a new ARP mediation process is needed.
Accordingly, there is a need for systems, apparatus, and methods that improve upon conventional approaches including the improved methods, system and apparatus provided hereby.